An experimental study of thermal management of rack of servers of a data centers is presented for different schemes of server’s power loadings. Four scheme of server’s power loading (uniform, discrete, segmented and clustered) are considered. A total of eleven cases of servers loading conditions are investigated. Temperature distributions and dimensionless measuring indices (SHI/RHI) are used to measure and evaluate the thermal management of the data center. The results showed that (i) uniform power loadingprovides the best results for (SHI/RHI) among the other schemesconsidered where the optimum benefit of cold air in server cooling is obtained at uniformly power loading of servers, (ii) clustering of active servers lead to better air flow management compared to discretely individual active servers and segmented distributions of active servers, and (iii) servers located at the bottom rack cabinet always has better thermal performance compared to servers at higher levels.